JP2004143426A - Ladder-type blue light-emitting polymer with excellent thermal stability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ladder-type blue light-emitting polymer brought to have excellent thermal stability by combining a blue light-emitting monomer with a polymer main chain of the polymer, subsequently polymerizing the monomer or polymerizing after adding fluorene to styrene monomer. <P>SOLUTION: The blue light-emitting polymer has ≥400°C high glass transition temperature and 5% mass reduction temperature. Therefore, the polymer is not only used as a blue light-emitting material for display but applied as a light-emitting case of domestic electric appliances and a light-emitting case for cellular phones through blends with resin polymers. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a light emitting polymer, and more particularly, to a ladder-shaped blue light emitting polymer having excellent thermal stability, which is polymerized by combining a polymer main chain with a blue light emitting monomer.

Polymers are generally classified as nonconductors and could not be used as electrical materials. However, as conductive polymers such as polyaniline, polypyrrole, and polythiophene have been developed, excellent materials having both the conductivity of metal and the light weight and processability of polymers have begun to appear.

Conjugated polymers having electrical and optical properties have been used in antistatic agents, sensors, electrodes, transistors, luminescent materials, solar cells, smart cards, electronic newspapers, displays, and the like. Polymer light-emitting materials have made great strides since the first publication of an electroluminescent phenomenon using poly (1,4-phenylvinylene) at Cambridge University in the UK in 1990. Compared to semiconductor inorganic materials, it is lighter, thinner, self-luminous, low voltage drive, fast switching speed, easy processability and low production cost, low dielectric constant, various development possibilities, etc. It is attracting attention as a material. In addition, there is an advantage that processing can be easily performed while adjusting electrical and optical properties through conversion of a molecular structure.

The blue light emitting polymer mainly utilizes an aromatic compound such as fluorene or spirofluorene as a conjugated polymer of the main chain. Examples are well shown in U.S. Patent Nos. 5,593,788, 5,597,890, 5,763,636, 5,903,027 and the like. In US Pat. No. 5,980,945, a light emitting device was manufactured using a polymer obtained by copolymerizing fluorene and anthracene. Further, copolymers of fluorene and an aromatic amine compound (for example, carbazole) are well shown in German Patent Nos. 19846766, 19846767, and 19846768. When manufacturing an electroluminescent device through a mixture of a luminous body and a polymer having a very low absorbance in visible light (e.g., polycarbonate, polystyrene, polymethacrylate, polyvinyl carbazole, etc.), it was disclosed in US Pat. . Recently, applications to organic semiconductors using thin films have been studied (Appl. Phys. Lett. 80 (6), 1088).

However, to date, there have been many improvements in blue light-emitting polymers in terms of life and luminance in light-emitting device applications. The main cause is heat. It is presumed that the motion of the polymer is caused by the heat, and the motion is caused by fine crystals or polymer aggregation. Since the generation of heat is increased in proportion to the use time of the electroluminescent device, it is difficult to expect a long life if the glass transition temperature, melting temperature or thermal stability of the light emitting polymer is 300 ° C. or less. That is, since the existing light emitting polymer had a glass transition temperature at which molecules started to move around 100 ° C. (Macromolecules; 1998; 31 (4); 1099-1103), the above-mentioned problems and the like were exhibited.
U.S. Pat.No. 5,593,788 US Patent No. 5597890 US Patent No. 5763636 U.S. Pat.No. 5,900,327 US Patent No. 5998045

The present invention has been proposed to solve the above problems and the like, and has as its object to produce a blue light emitting polymer having high solubility and excellent thermal stability.

The object of the present invention is to combine a blue light-emitting monomer with a polymer main chain, polymerize the polymer or attach fluorene to a styrene monomer, and then polymerize the resulting polymer, thereby improving thermal stability. Achieved by a ladder-shaped blue emitting polymer.

The present invention as described above will be described in more detail as follows.
The present invention is for producing a blue light emitting polymer having high thermal stability, and unlike a conventional light emitting polymer having a glass transition temperature of 100 ° C. or lower, by giving a ladder form. We propose a new luminescent polymer structure with improved thermal stability. In particular, the glass transition temperature, which indicates molecular behavior, is as high as 400 ° C or higher, and the temperature at which the mass is reduced by 5% on thermal analysis (TGA) is 450 ° C or higher. It is. Polystyrene, which is a component of the main chain, is transparent in the visible light region, increases compatibility with other polymers, and blocks molecular movement on one axis of the ladder-shaped polymer to improve thermal stability.

The existing polyfluorene or polyallyl polymer has the morphological structure shown in FIG. 1 (a), and the movement of the molecule becomes active at a high temperature, making it difficult to have a glass transition temperature of 100 ° C. or more. The ladder polymer is configured as shown in FIG. As shown in (b), the A block is a light emitting portion, and the B block is a polystyrene having excellent optical performance, excellent thermal stability, and inhibiting the movement of molecules. Further, the polystyrene block is well dissolved in a solvent, and it is easy to produce a thin film.
Therefore, the present invention provides a blue light emitting polymer represented by FIG. 1 (b).

In the formula of FIG. 1 (b), A is polyfluorene, polythiophene, polypyrrole, polycarbazole, polycarbazole, polyphenylene, polyaniline, polypyridine; B is polystyrene (polystyrene), polypyrrole (polypyrrol), polythiophene (polythiophene), polyphenylene (polyphenylene), polyaniline (polyaniline), polypyridine (polypyridine), polycarbazole (polycarbazole); n is an integer of 5 to 100; And m is an integer of 2 to 100.

　また、本発明は上記化学式１でAr化合物をさらに含有する、下記化学式２の青色発光高分子を提供する。

　上記式において、Arはアロマチック化合物であって、フルオレン(fluorene)、フルオレン誘導体(fluorene derivatives)、ベンゼン(benzene)、ベンゼン誘導体(benzene derivatives)、チオフェン(thiophene)、チオフェン誘導体(thiophene derivatives)、カルバゾール(carbazole)、カルバゾール誘導体(carbazole derivatives)、ピリジン(pyridine)、ピリジン誘導体(pyridine derivatives)である。
　特に、上記化学式１または２において、Bはアタクチック(atactic)あるいはシンジオタクチック(syndiotactic)構造を有するポリスチレン(polystyrene)である青色発光高分子(ladder-type blue light emitting polymers )が好ましい。 In the formula of FIG. 1 (b), A is a polyfluorene, and B is a polystyrene.

The present invention also provides a blue light emitting polymer represented by the following Chemical Formula 2, further comprising an Ar compound represented by the above Chemical Formula 1.

In the above formula, Ar is an aromatic compound, fluorene (fluorene), fluorene derivatives (fluorene derivatives), benzene (benzene), benzene derivatives (benzene derivatives), thiophene (thiophene), thiophene derivatives (thiophene derivatives), carbazole (carbazole), carbazole derivatives, pyridine, and pyridine derivatives.
In particular, in Formula 1 or 2, B is preferably a ladder-type blue light emitting polymer, which is a polystyrene having an atactic or syndiotactic structure.

The method for producing the ladder-shaped blue light-emitting polymer as described above can be produced by various methods.
The first method is a method of removing fluorene or dibromofluorene at the 9-position hydrogen using normal butyl lithium under an ether solvent, and then combining with polyvinyl benzene chloride and performing allyl polymerization using an iron or nickel catalyst. .

The second method is a method in which chloride of vinylbenzene chloride is substituted with fluorene, styrene is polymerized, and then fluorene is polymerized with an iron or nickel catalyst. Another method is to polymerize vinylfluorene (chemical formula 3) or copolymerize styrene and vinylfluorene (chemical formula 4), and then polymerize a fluorene group or the like.

UV The UV-Visible absorbance of the produced polymer was obtained at a wavelength of 360 nm (FIG. 3), and the blue emission wavelengths of P1 and P2 were shown to be around 450 to 540 nm (FIG. 4). In addition, the points of 5% weight loss on TGA of P1 and P2 were 475 and 448, respectively, which showed very excellent results in terms of thermal stability (FIGS. 5 and 6). According to DSC analysis, the glass transition temperature was 400 ° C. or higher, and no melting temperature was observed.

高分子 When the polymer light emitting material is manufactured by the above method, it is possible to expect a phase stability and a long life while maintaining the luminous efficiency. In addition, a polymer can be coated on the electrode by using spin-coating at the time of device manufacturing, and the compatibility with a polymer having good optical performance (for example, polycarbonate, polymethyl methacrylate, polystyrene) is improved. Can be.

Incidentally, it can be copolymerized with an aromatic compound. At this time, the compound can be an aromatic compound such as fluorene, a fluorene derivative, benzene, a benzene derivative, a thiophene, a thiophene derivative, carbazole, a carbazole derivative, pyridine, a pyridine derivative, styrene, a styrene derivative, and the like.

機器 The equipment used for the polymer analysis was as follows. Gel permeation chromatography was used after correcting with polystyrene using a Viscotec product. The solvent used was tetrahydrofuran, which was measured at 40 ° C. by the refractive index. UV-visible spectrum was obtained using JASCO V-570, and 1H-NMR spectrum was obtained using Varian Unit Inova 200 (200 MHz). TGA was measured using a Perkin-Elmer TGC # 7/7 while increasing the temperature at 20 ° C. per minute in a nitrogen atmosphere. Photoluminescence spectra was measured using a spctrapro 275i and 300i from Acton as spectrometer, W-lamp as light source, and equipment equipped with a CCD camera.

Hereinafter, the present invention will be further embodied with reference to examples, but the present invention is not limited thereto.

1. 9-vinylbenzylfluorene Fluorene (10.0 mmol) is reacted with t-butyllithium (1.7 M in pentane, 10.0 mol) in tetrahydrofuran (10 mL) at -78 ° C for 2 hours to produce lithium fluorene. The resulting fluorene lithium is gradually added to a solution of vinylbenzene chloride (10 mmol) in tetrahydrofuran at −78 ° C., and is reacted for 16 hours with stirring. Water (100 mL) and ether (100 mL) are added in this order, followed by stirring. After extracting and drying the organic solution layer, it was recrystallized to obtain an ivory needle-like solid. ¹ H-NMR (200 MHz, CDCl ₃ ) is 7.77 (2H, d, Fu-H), 7.39-7.20 (10H, m, Fu-H, Bn-H), 6.80-6.66 (1H, q, Vy -H), 5.80-5.70 (1H, d, Vy-H), 5.27-5.21 (1H, d, Vy-H), 4.23 (1H, t, Fu-H), 3.10 (1H, d, Bz) is there.

2. Synthesis of polyvinylbenzyldibromofluorene Under a nitrogen atmosphere, polyvinylbenzylchloride (1.57 g, Mw 55,000) was dissolved in tetrahydrofuran (20 mL). After dibromofluorene (3.24 g) was dissolved in tetrahydrofuran (50 mL), the temperature was reduced to dry ice / acetone. After adding 4 mL of normal butyllithium (2.5 M, normal hexane solution), the resulting solution was gradually added to the polyvinylbenzyl chloride solution. After the mixture was stirred at room temperature for 6 hours, water was added. The resulting product was extracted with ethyl ether (200 mL) and dried under vacuum. After drying, it was obtained in the form of a yellow solid. The molecular weight is 272,900, the molecular weight distribution is 5.71, and the UV-Vis (λmax, THF) is 298 nm.

3. Synthesis of polyvinylbenzylfluorene Under a nitrogen atmosphere, polyvinylbenzylchloride (1.57 g, Mw 55,000) was dissolved in tetrahydrofuran (20 mL). After fluorene (1.67 g) was dissolved in tetrahydrofuran (50 mL), the temperature was reduced to dry ice / acetone. After adding 4 mL of normal butyllithium (2.5 M, normal hexane solution), the resulting solution was gradually added to the polyvinylbenzyl chloride solution. After the mixture was stirred at room temperature for 6 hours, water was added. The resulting product was extracted with ethyl ether (200 mL) and dried under vacuum. After drying, a yellow solid was obtained. The molecular weight is 68,160, the molecular weight distribution is 2.96, and the UV-Vis (λmax, THF) is 302 nm.

4. Synthesis of polyvinylbenzyl-polyfluorene (P1)
Under a nitrogen atmosphere, polyvinylbenzylfluorene (1.57 g, Mw 55,000) and dihexylfluorene (3 g) were dissolved in chloroform (20 mL). After charging FeCl ₃ (5 g), the mixture was stirred at room temperature for 4 hours. After methanol was added to the mixture, the resulting precipitate was filtered. After dissolving the obtained solid in tetrahydrofuran, the insoluble solid was removed. The resulting solution was dried using vacuum to yield the product as a yellow powder. The molecular weight is 79,040, the molecular weight distribution is 2.94, the UV-Vis (λmax, THF) is 362 nm, the PL (λmax, THF) is 542 nm, the TGA (5%, ° C) is 475, and the glass transition temperature (° C) is 421.8.

5. Synthesis of polyvinylbenzyl-polyfluorene (P2)
Under a nitrogen atmosphere, polyvinylbenzyldibromofluorene (1.57 g, Mw 55,000) and dihexylfluorene (3 g) were dissolved in chloroform (20 mL). After charging FeCl ₃ (5 g), the mixture was stirred at room temperature for 4 hours. After methanol was added to the mixture, the resulting precipitate was filtered. After dissolving the obtained solid in tetrahydrofuran, the insoluble solid was removed. The resulting solution was dried using vacuum to yield the product as a yellow powder. The molecular weight is 132,200, the molecular weight distribution is 2.07, UV-Vis (λmax, THF) is 362 nm, PL (λmax, THF) is 514 nm, TGA (5%, ° C) is 448, and glass transition temperature (° C) is 404.4.

6. Synthesis of polyvinylbenzyl-polyfluorene (P3)
Under a nitrogen atmosphere, polyvinylbenzyldibromofluorene (1.57 g, Mw 55,000) and dihexylfluorene (3 g) were dissolved in benzene (20 mL). After charging Pd (PPh ₃ ) _{4 (} 5 g), the mixture was stirred at the boiling point for 6 hours. After methanol was added to the mixture, the resulting precipitate was filtered. After dissolving the obtained solid in tetrahydrofuran, the insoluble solid was removed. The resulting solution was dried using vacuum to yield the product as a yellow powder. The molecular weight is 159,300, the molecular weight distribution is 4.34, UV-Vis (λmax, THF) is 330 nm, and PL (λmax, THF) is 445 nm.

7. Synthesis of polyvinylbenzyl-poly (fluorene-co-thiophene) (P4)
Under a nitrogen atmosphere, polyvinylbenzyldibromofluorene (500 mg, Mw 55,000) and 3-octylthiophene (2 g) were dissolved in chloroform (20 mL). After charging FeCl ₃ (2.5 g), the mixture was stirred at room temperature for 4 hours. After methanol was added to the mixture, the resulting precipitate was filtered. After dissolving the obtained solid in tetrahydrofuran, the insoluble solid was removed. The resulting solution was dried using vacuum to yield the product as a yellow powder. The molecular weight is 8,911, the molecular weight distribution is 3.14, UV-Vis (λmax, THF) is 405 nm, PL (λmax, THF) is 544, 682 nm, TGA (5%, ° C) is 280, and glass transition temperature (° C) is 384.8. is there.

8. After putting a magnetic bar into a 100 ml round-bottomed syndiotactic polyvinylbenzylfluorene flask and replacing with nitrogen, 2 mmol (0.52 g) of 1-vinyl-4- (1-fluorenyl) methylbenzene was added, Toluene (20 ml) was added and dissolved. 12.1 mmol (2.43 M, 5 ml) of MAO as a cocatalyst was gradually added thereto, followed by stirring for 30 minutes. Next, 10 mmol (2.19 mg) of CpTiCl _{3 as a} main catalyst is dissolved in 1 ml of toluene, and then slowly added dropwise at room temperature. After the dropwise addition, the mixture was stirred at room temperature for 1 hour, and the solution was poured into 200 ml of methanol to which HCl was added to obtain a solid. The solid was washed with methanol, and dried under vacuum for several hours to obtain 0.3 g of a polymer. The molecular weight is 2,500.

9. Syndiotactic polyvinylbenzylfluorene-co-styrene (P5)
After a magnetic bar was placed in a 100 ml eggplant-shaped round flask and replaced with nitrogen, 20 mmol (2.1 g) of styrene and 2 mmol (0.52 g) of 1-vinyl-4- (1-fluorenyl) methylbenzene were added, and toluene ( 20 ml) and dissolved. 12.1 mmol (2.43 M, 5 ml) of MAO as a cocatalyst was gradually added thereto, followed by stirring for 30 minutes. Next, 10 mmol (2.19 mg) of CpTiCl _{3 as a} main catalyst is dissolved in 1 ml of toluene, and then slowly added dropwise at room temperature. After the dropwise addition, the mixture was stirred at room temperature for 2 hours, and the solution was poured into 200 ml of methanol to which HCl was added to obtain a solid. The solid was washed with methanol, and dried under vacuum for several hours to obtain 2.5 g of a copolymer. The molecular weight is 8,000.

10. Syndiotactic polystyrene-polyfluorene (P6)
Under a nitrogen atmosphere, P5 (500 mg, Mw 8,000) was dissolved in chloroform (20 mL). After charging FeCl ₃ (2.5 g), the mixture was stirred at room temperature for 4 hours. After methanol was added to the mixture, the resulting precipitate was filtered. After dissolving the obtained solid in tetrahydrofuran, the insoluble solid was removed. The resulting solution was dried using vacuum to yield the product as a yellow powder. The molecular weight is 4,802 and the molecular weight distribution is 2.42. UV-Vis (λmax, THF) is 353 nm, PL (λmax, THF) is 460 nm, TGA (5%, ° C) is 232.8, and glass transition temperature (° C) is 413.5.

Effect of the Invention As described in detail above, the high molecular weight blue light emitting polymer prepared according to the present invention has a high glass transition temperature and a 5% weight loss temperature point. Therefore, it can be used not only as a blue light-emitting material for display but also as a light-emitting case for home appliances and a light-emitting case for mobile phones through blending with a resin polymer.

(A) is a conceptual diagram of an existing allyl blue light emitting polymer, and (b) is a conceptual diagram of a ladder type blue light emitting polymer. It is a figure which shows the manufacturing method of a ladder type light emitting polymer. It is a figure which shows UV-Visible absorbance. It is a figure which shows an emission spectrum. It is a figure which shows TGA (thermal analysis) of P1. It is a figure which shows TGA (thermal analysis) of P2.

Claims (4)

A blue light emitting polymer having a ladder structure as shown below.

In the above formula, A is polyfluorene, polythiophene, polypyrrole, polycarbazole, polyphenylene, polyaniline, polypyridine; B is polystyrene, polypyrrole, polythiophene, polyphenylene, polyaniline, polypyridine, polycarbazole; n is an integer of 5 to 100 And m is an integer from 2 to 100. The blue light-emitting polymer according to claim 1, wherein A is porfluorene and B is polystyrene, having the following structural formula.

The blue light-emitting polymer according to claim 2, further comprising Ar and having the following structural formula.

In the above formula, Ar is an aromatic compound, and is fluorene, a fluorene derivative, benzene, a benzene derivative, a thiophene, a thiophene derivative, a carbazole, a carbazole derivative, a pyridine, or a pyridine derivative. 4. The blue light-emitting polymer according to claim 2, wherein B is a polystyrene having an atactic or syndiotactic structure.

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